1. Field of the Disclosure
The present disclosure relates to a transformer hybrid, and more particularly, to a transformer hybrid with multiple input terminals.
2. Description of the Related Art
As the communication technology such as mobile phone, internet and digital TV become more popular and growth rapidly, the need of high quality and low cost CMOS power amplifier is increasing. However, one of the main problems of the current CMOS process is the low breakdown voltage and the high substrate loss of the silicon, therefore, the approach of power combination through the transformer or hybrid is proposed in order to reduce the area of the transistors as well as increase the output power and efficiency.
However, traditional transformer combiners would produce large peak voltage when power cells are operated with phase difference. And traditional hybrid that implemented by transmission lines or lots of passive components is too large for chip design.
Therefore, the transformer hybrid is very suitable to the mobile power amplifiers that requires high linearity and high output power level.